This invention relates generally to oscillators and more particularly to high power field- effect transistor oscillators.
Gallium arsenide field effect transistor oscillators (hereinafter GaAs FET oscillators) have proven particularly useful as high power, high frequency microwave oscillators. Such oscillators as set forth, for example in U.S. Pat. No. 4,135,168, issued to Paul C. Wade on June 16, 1979, typically utilize a GaAs FET connected in a common-drain configuration oscillator. Positive feedback is provided through a frequency-determining network that employs a single independently voltage-tunable circuit element, such as a varactor diode. Varactor diodes are semiconductor devices characterized by a voltage sensitive capacitance that resides in the space charge region at the surface of the semiconductor bounded by an insulating layer and which may be used to tune the capacitance of a tuned circuit. Heretofore, these oscillators have not been capable of achieving maximum tuning bandwidth with the GaAs FET operating at optimum efficiency across the band.